WASHINGTON —
Authorities in the southwestern U.S. state of Texas say several people have been killed and more than 100 others injured in a massive explosion at a fertilizer plant Wednesday evening.

The blast occurred as firefighters in the small town of West were trying to extinguish a fire at the plant shortly before nightfall. An official with the Texas Department of Public Safety says between 50-75 houses near the plant were destroyed.

"I can tell you I was there. I walked through the blast area, I searched some houses earlier tonight. Massive, just like Iraq, just like the Murray building in Oklahoma City. Same kind of anhydrous [ammonia] exploded, so you can imagine what kind of damage we're looking at there," he said.

Many residents of the community were evacuated, including more than 100 elderly residents at a nursing home that was badly damaged in the blast. Emergency crews began a house-to-house search of the area to find anyone who may still be trapped.

An official with the Waco police department says some firefighters from the town of West are missing.

Additional emergency crews from dozens of nearby towns and counties were called in to respond to the disaster. And Texas Governor Rick Perry says state resources have been mobilized to assist local authorities.